@TimStone are you talking about the protocol used to navigate MSE (I always use HTTPS there) or about the protocol embedded in the link?
– SEJPMMar 7 '17 at 15:57

@TimStone not here, it happens when you try to link to a question on different site, e.g. to this question on Cryptography.SE as OP did, or from any other non MSE site.
– Shadow WizardMar 7 '17 at 15:57

@SEJPM The protocol in the link; the only example I see in your edit history is a http -> https swap (and the http variant works for me), but maybe that's not the one you're referring to
– Tim StoneMar 7 '17 at 16:09

@Tim oh, so it never worked? Might be, not 100% sure about that. If so you can write answer here quoting the restrictions, saying that links from main sites to other main sites are not parsed.
– Shadow WizardMar 7 '17 at 16:15

OK, so the issues I demonstrated here and on crypto are links to other questions on the same site (ie crypto -> crypto and MSE -> MSE). They do appear for me regardless of whether the link uses http or https. It may have something to do with the fact that I use HTTPS Everywhere (which seems to break subtle details more often than not on SE it appears). The original crypto reference Q is this one. My edits on this Q was a HTTP -> HTTPS conversion (I encountered the bug pre- and post-edit) and here a HTTPS -> HTTP -> HTTPS test.
– SEJPMMar 7 '17 at 16:19

1

Ohhh, yeah, I see now @SEJPM. The API request is still using JSONP (whyyyyy?) and does so over HTTP exclusively, so the insecure request is blocked when you're browsing the site via HTTPS. Several simultaneous bugs here!
– Tim StoneMar 7 '17 at 16:21